x-4 man: there are basically two trigger lengths as mentioned. Long and short. Many target or bulls eye shooters prefer the longer trigger so that just the forward pad of the trigger finger rests on the trigger as many consider this a proper finger position for target work.
Many other shooters prefer the shorter trigger for carry/defense purposes so that when the access the pistol (grab the gun), the trigger finger need not be so crucially positioned and the trigger can be pulled effectively with any part of the finger that touches it.
This being said, there are bunches of different triggers and trigger styles to look at but for length it is either short or long. You can get long triggers with holes cut out for lighter weight, slots cut out for the same purpose; you can get them in steel, aluminum or plastic. Most of the shorter triggers closely ressemble the military short trigger but come in different materials.
I used two Chip McCormick triggers for my two 45s. They are of the longer style but made of a plastic or bakelite material. I smoothed the face of both triggers to slightly shorted the trigger length and to also give me a smooth trigger, which I prefer over one with serrations. Both triggers now match my style of shooting for each of the two pistols and I am quite happy with them both. HTH. Mikey.